Determination of Nursery Areas and Movement Patterns of the Scalloped Hammerhead Sphyrna Lewini in the Mexican Pacific through Vertebrae Microchemistry

The scalloped hammerhead shark is a target species of many small-scale fisheries across Mexico, with landings comprised mainly of juvenile organisms. The presence of young-of-the-year, juveniles and gravid females in the Mexican Pacific suggests that there are many important natal and nursery areas for this species, although the decreasing catch rates since the early 80´s suggest negative impacts on their stocks. Essential management information such as residency time at every habitat, abundance at nursery areas, and philopatry remains unknown. Critical habitat areas and fisheries refuge zones are needed in order to counterbalance fisheries effects, as they promote population continuity through reproduction, growth and recruitment. At present this fishery is regulated by Federal regulations, however they are incomplete because it lacks information on migration patterns and habitat use of hammerhead shark. This study is aimed at determine nursery areas, sex and age related changes in habitat use and movement patterns of this species using natural chemical markers in vertebrae of S. lewini with LA-ICP-MS. This study will provide complementary biological information to that obtained by classical genomic and tagging methods, seeking to give the information needed for proper  management and conservation policies for the hammerhead in  the Mexican Pacific.